The present invention relates to rugged and protective electrical junction boxes within which electrical wiring connections may be made. More particularly, the present invention relates to rugged and non-conductive electrical junction boxes which are useable for wiring installations including, for example, outdoor, partially subterranean, partially underwater, or weather-exposed wiring runs, to which a variety of installation circumstances may apply, and to which stringent electrical code requirements may pertain. Still more particularly, the present invention relates to an extraordinarily rugged electrical junction box which by its embodied combination, arrangement and cooperation of features allows unprecedented utility for its use in electrical wiring to light fixture installations at swimming pools.
Electrical junction boxes for wiring installations in wet environments are known in the pertinent art. These conventional junction boxes range from the simple, rather small metal or plastic variety used with conventional wire types, such as with Romex wire, for example, and are usable for inside residential wiring. The pertinent art also includes large, complex, and specially sealed junction boxes used in hazardous or flammable industrial environments, many times with specialized electrical cable constructions specific to the particular use.
However, few electrical wiring junction box uses are more demanding than those associated with electrical installations around swimming pools. With the proximity to water, and the necessary limited access by those not skilled as electricians (for example, access by a home owner for changing a lamp in a submerged swimming pool light fixture), the usual electrical code requirements are very demanding. Particularly, the American National Standards Institute/Underwriters Laboratories, Inc., (ANSI/UL) standard for junction boxes for swimming pool light fixtures (Standard for Safety, UL 1241), includes detailed and stringent requirements relating to all of: materials of construction; environmental sealing; electrical connections, electrical grounding, electrical bonding, and strain relief of wiring; voltage drop, available volume, and heat dissipation; as well as installation integrity factors (strength of mechanical connection between conduits and the junction box, for example).
All these standards for junction boxes usable in such environments as those around a swimming pool are intended to insure the safety of electrical wiring to lighting fixtures and to other facilities at and adjacent to swimming pools. Further, additional national standards (National Electrical Code, NFPA 70), as well as differing regional or municipal electrical code requirements may all apply to a particular swimming pool light fixture and other wiring installations. Thus, a multitude of differing combinations of code requirements may apply to swimming pool light fixture installations dependent on where they are located across the United States.
As a result, the electrical wiring industry has developed a very large number of standard junction boxes adapted to satisfy the generally applicable code requirements, to also satisfy the code requirements of certain locales, and to allow for a desired number of swimming pool light fixtures or other facilities at and adjacent to a swimming pool to be wired from the various junction boxes. Some of these conventional junction boxes are designed for use with metal (i.e., conductive) conduit (brass or aluminum, for example), while others are designed for use with nonconductive polyvinylchloride (PVC) conduit. Some junction boxes for swimming pool light installations and for other installations at or adjacent to a swimming pool are designed to satisfy the local requirements as to conduit size, or materials and will not satisfy the requirements of other localities. Some junction boxes are even custom designed and manufactured as ordered to satisfy the combination of code requirements of particular locales and to allow the desired number of light fixtures or other facilities to be wired from the junction box. That is, some locales require the use of plural junction boxes to wire a certain number of light fixtures, while another locale may allow a single standard or custom junction box to serve the same number of light fixtures. Alternatively, the expense and necessary waiting time of having a custom junction box designed and made may mitigate in favor of using plural common junction boxes to satisfy the needs of a particular swimming pool light installation, but at the expense of additional wiring and installation expense.
Further to the above, some conventional junction boxes are not sufficiently rugged as may be desired to withstand the impacts and collisions that such a box may experience at and around a swimming pool.
Still further, some locales may not allow a conventional non-metallic junction box to be used with an older installation utilizing metal (i.e., conductive) conduit. Many locales and codes require the connections at a junction box to all be bonded electrically to the metallic conduit. With conventional non-metallic junction boxes, such bonding of electrical connections within the junction box to the metallic conduit is not possible.
In view of the above, it is easy to understand why the wiring industry has developed plural swimming pool junction box designs, which are manufactured in plural sizes to meet varying installation needs. Of course, this variety in junction box designs and sizes means a great burden in junction box inventory for manufacturers and distributors, in installation logistics to insure that the right junction box design and size is available and is used at a certain job, and in inspection of wiring installations because of the multitude of codes applicable and the challenge in determining whether the junction boxes actually used out of the multitude of boxes available do in fact satisfy the plural applicable code requirements. Of course, all of this leads to a resulting increase in the chances for error and disagreement between planners, installers, and inspectors, with resulting rework of wiring installations and loss of time and productivity.
In view of the deficiencies of the related technology, it is an object for this invention to reduce or eliminate at least one of these deficiencies.
More particularly, it is an object for this invention to provide a rugged electrical junction box suitable for installation in wet environments.
Still more particularly, the rugged junction box according to the present invention has as an object the provision of a junction box structure in which a base member of the junction box in a particularly preferred embodiment is nested with a cover portion, which cover portion is formed of particularly impact resistant material.
As described above, it will be appreciated that, and recognized as an object for this invention, that the inventive junction box according to one preferred embodiment is particularly rugged because the base member and cover portion together provide a double-wall perimeter wall structure for the junction box. In this structure, the cover portion is made of an electrically non-conductive polymer that is also particularly impact resistant. Further, the base member has a perimeter wall section formed of non-conductive polymer material, and which is disposed behind (i.e., inwardly of) the perimeter wall section of the cover member, and which base member wall section backs up and reinforces the perimeter wall section of the cover portion.
It is an object for this invention to provide such a junction box with a particularly preferred embodiment having a double-wall perimeter wall structure, in which the perimeter wall structure is particularly impact and penetration resistant.
Thus, the present invention provides a non-conductive rugged electrical junction box particularly for wet environments, the junction box comprising: a body member formed of non-conductive material, the body member including a back wall and plural side walls interconnecting with one another, the back wall and side walls cooperatively defining a cavity, and the side walls having generally coplanar end edges defining an opening to the cavity; one of the side walls defining at least one depending through bore for passage of electrical wires upwardly into the junction box, and the side wall outwardly defining a depending tubular boss circumscribing the through bore; the back wall defining at least one protruding strain relief structure above and aligned generally with the through bore, and the back wall further defining a plateau structure; a bonding bar disposed at the plateau structure, and the bonding bar defining plural cross slots each having a pair of opposed arcuate grooves cooperatively defining a circumferentially interrupted screw thread for receiving a binding screw for securing and electrically connecting an electrical conductor in a respective one of the plural bonding bar slots; a cover member sealingly cooperable with the end edges of the side walls to sealingly close the cavity.
Accordingly, one embodiment of the present invention provides a rugged, impact resistant non-conductive electrical junction box particularly for wet environments, the junction box comprising: a nested two-part body formed of non-conductive material, the body including: a base part having a back wall and plural side walls interconnecting with one another, the back wall and side walls cooperatively defining a cavity, and the side walls defining an opening to the cavity; one of the side walls defining a through bore for passage of electrical wires upwardly into the junction box, and outwardly defining a depending tubular boss circumscribing the through bore; a cover member having a wall closing the opening of the base part, and the cover member including plural side walls nesting with respective side walls of the base part, so that the side walls of the base part and the side walls of the cover member form a dual wall structure along each side of the junction box. These and additional advantages of the present invention may be further appreciated from a reading of the appended detailed description of a preferred embodiment of the invention, taken in conjunction with the attached drawing figures.